I believe the answer is that Osensei was disallowed from showing the solo exercises that he learned in DR. That kind of approach has made it to the States in various forms and has been producing impressive results.

If that belief could be substantiated, that would be an impressive breakthrough in understanding the spread of aikido and its development as a MMA---mass martial art :-)

I for example still don't get what the difference is between aikido and its parent art: perhaps the answer is so simple---a "martially diminished" form that was permitted to be propagated to the public intertwined a spirituality in line with O-Sensei's philosophy of moral education? [aside: if O-Sensei was not permitted to reveal many things he had learnt, are his successors bound by the same mores?]